Group the module crates under modules/

The service pseudo-clients and the ircd protocol link sat flat at the
repo root, mixed in with the daemon core and the SDK. Move them all
under modules/ so the tree separates concerns cleanly: the daemon in
src/, the SDK every module links against in api/, and the loadable
modules — the pseudo-clients plus the protocol link — in modules/.

Workspace members, the daemon's per-crate dependency paths, and each
module's api path are updated to match; the docs follow. No code change.

modules/chanserv/src/invite.rs

@@ -0,0 +1,26 @@
+use fedserv_api::Store;
+use fedserv_api::{Sender, ServiceCtx};
+use fedserv_api::NetView;
+
+// INVITE <#channel> [nick]: invite a user (self if no nick) into the channel.
+pub fn handle(me: &str, from: &Sender, args: &[&str], ctx: &mut ServiceCtx, net: &dyn NetView, db: &dyn Store) {
+    let Some(&chan) = args.get(1) else {
+        ctx.notice(me, from.uid, "Syntax: INVITE <#channel> [nick]");
+        return;
+    };
+    if !super::require_op(me, from, chan, ctx, db) {
+        return;
+    }
+    let target = match args.get(2) {
+        Some(&nick) => match net.uid_by_nick(nick) {
+            Some(u) => u.to_string(),
+            None => {
+                ctx.notice(me, from.uid, format!("\x02{nick}\x02 isn't here."));
+                return;
+            }
+        },
+        None => from.uid.to_string(),
+    };
+    ctx.invite(me, &target, chan);
+    ctx.notice(me, from.uid, format!("Invited to \x02{chan}\x02."));
+}